The overall goal of this program is to investigate the central neural events which underlie the altered or impaired attention in two human disease states: schizophrenia and petit mal epilepsy. The objectives are to be able to describe the possible etiological role of central nervous system pathology in these diseases; to understand the nature of the relationship between this pathology and the specific behavioral symptom of impaired attention, as well as the other behavioral symptoms of these diseases; and ultimately, to be able to provide suggestions with respects to remediation and/or prevention. The independent variables include primarily electrical stimulation of the brain, the production of specific subcortical lesions (by electrocoagulation, by aluminum hydroxide cream and by specific intrauterine insults) and the use of centrally-acting drugs (stimulants, sedatives, tranquilizers, convulsants, narcotics). In specific instances, these variables are used in combination (e.g., brain stimulation or lesions and drug administration). The dependent variables are primarily behavioral (attentive and cognitive behavior) but these are studied in conjunction with the electrical activity of the brain (background EEG, evoked potentials) analyzed either by hand or by digital computer methods. In addition to the above studies, experiments are currently underway exploring the effects in the rat of narcotic analgesics on thresholds to stimulation of the positive intracranial reinforcement or the negative intracranial reinforcement areas of the brain.